1. Field of the Invention
The present invention relates generally to systems for forming concrete. More specifically, the present invention concerns a modular forming system for box culverts that utilizes a modular header and a modular pallet each including segmented members formed from a cast material and interconnected with a plurality of keys. The inventive configuration provides a forming system that is stronger, more durable, and more efficiently assembled than existing forming systems.
2. Discussion of Prior Art
Those ordinarily skilled in the construction industry will appreciate that precast concrete box culverts are a desired solution over cast-in-place culverts for a wide variety of applications such as highway bridges and drainage conditions, such as storm and sanitary sewers. These pre-cast culverts come in a variety of sizes (e.g., various rises, spans, thicknesses, etc.) and can be joined together at the ends (e.g., with mastic, gaskets, etc.) to form the desired run.
Forming systems for forming the pre-cast concrete box culverts are known in the art. These prior art forming systems typically include adjustable cores, jackets, and pallets. The adjustable cores, jackets, and pallets include segments formed from fabricated sheet steel that are bolted together to form the desired sized form. These prior art forming systems further include a non-adjustable header ring fabricated from sheet steel and an adjustable dead weight header frame for pressing the header ring down between the core and the jacket.
These prior art forming systems are problematic and subject to several limitations. For example, the assembly of the prior art systems is very labor-intensive, requiring two workers as long as a day and a half to assemble the multitude of necessary bolts. Additionally, during vibration of the forms, the bolts are undesirably prone to becoming loose and thereby compromising the mold. Furthermore, in order to change the size of culvert being formed, a separate header ring is required and thus must either be manufactured, or inventoried and the header frame must further be adjusted to cooperate with the separate ring. These problems and limitations are undesirable in that they add increased labor and/or expense to assembling the forming systems. In addition, such sheet steel components, and in particular the header components, make a limited contribution to densification of the concrete.
The present invention provides an improved modular forming system for box culverts that does not suffer from the problems and limitations of the prior art forming systems detailed above. The inventive forming system enables a strong and secure system that is relatively easier and more efficient to assemble.
A first aspect of the present invention concerns a header for use with a pallet, a jacket supported on the pallet, and a core encircled by the jacket to define a form for forming concrete received therebetween into box culverts having opposite faces. The header broadly includes a plurality of members removably couplable to one another so that when the members are coupled together they are operable to encircle the core and slide between the core and the jacket to contact concrete received therebetween to form one of the faces of the box culvert, and a key. Each member includes at least one channel defined therein being sized and dimensioned to cooperate with the channel in an adjacent member to define a keyway. The key is sized and dimensioned to be slidably received in the keyway to thereby removably couple the adjacent members.
A second aspect of the present invention concerns a pallet for use with a core, a jacket encircling the core, and a header slidable between the core and the jacket to define a form for forming concrete received therebetween into box culverts having opposite faces. The pallet broadly includes a plurality of members removably couplable to one another so that when the members are coupled together they are operable to encircle the core and support the jacket to contact concrete received therebetween to form one of the faces of the box culvert, and a key. Each member includes at least one channel defined therein being sized and dimensioned to cooperate with the channel in an adjacent member to define a keyway. The key is sized and dimensioned to be slidably received in the keyway to thereby removably couple the adjacent members.
A third aspect of the present invention concerns a key for removably coupling at least two segments of a segmented casting form wherein each segment includes at least one channel defined therein being sized and dimensioned to cooperate with the channel of an adjacent segment to define a keyway. The key broadly includes a pair of spaced apart ridge sections, a transverse section spanning the space between the ridge sections and thereby joining the ridge sections together, and a locking mechanism to selectively prevent removal of each of the ridge sections from the respective channel when the key is received in the keyway. Each ridge section is sized and dimensioned to be slidably received in one of the channels. The transverse section is sized and dimensioned so that when one of the ridge sections is received in one of the channels of one of the segments and the other ridge section is received in the channel of the adjacent segment, the segments are generally in a sealing relationship with one another.
A fourth aspect of the present invention concerns a modular forming system for forming concrete into a box culvert having opposite faces. The system broadly includes a core operable to mold the inside circumferential surface of the culvert, a pallet encircling the core and being operable to mold one of the faces of the culvert, a jacket supported on the pallet and spaced from the core and being operable to mold the outside circumferential surface of the culvert, a header encircling the core and being operable to slide between the core and the jacket and being operable to mold the other face of the culvert, and a plurality of keys. The pallet includes a plurality of pallet members removably couplable to one another so that when the pallet members are coupled together they are operable to encircle the core to contact concrete received therebetween to form the one of the faces of the box culvert. Each pallet member includes at least one pallet channel defined therein being sized and dimensioned to cooperate with the pallet channel in an adjacent pallet member to define a pallet keyway. The header includes a plurality of header members removably couplable to one another so that when the header members are coupled together they are operable to encircle the core and slide between the core and the jacket to contact concrete received therebetween to form the other face of the box culvert. Each header member includes at least one header channel defined therein being sized and dimensioned to cooperate with the header channel in an adjacent header member to define a header keyway. Each key is sized and dimensioned to be slidably received in the pallet and header keyways to thereby removably couple the respective adjacent members.
In a preferred embodiment of the forming system, adjacent members include complementing alignment pins and pin-receiving apertures that provide quick alignment of the members to present the keyways for quick interconnection of the adjacent members with the keys. In the preferred embodiment, when adjacent members are properly aligned, the keyways formed therein are oriented such that the keys can be easily slidably received therein to provide a secure interconnection, however, the keyways resist accumulation of concrete therein. The preferred embodiment further includes a mechanism for quickly and easily removing the keys from the keyways for disassembly of the forming system.
Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.